Forum sponsored by:

Horses for Courses

Or Metals for purposes

Search for: in Thread Title in

Wolfie	09/12/2010 23:52:49
502 forum posts	OK I have just been studying the plans for my Stuart engine as I intend to buy some metal at the ME show. (Attending on Sat, look out for a badge with the Wolf on) But how set in stone are such things? Why are some things brass and others mild steel. And why are the odd few bits cast iron? And what the hell is 'finished' ?? My plans designate one particular part as 'finished' in the materials column. And whats the difference between silver steel and stainless steel?? And how do I tell what already in my stash is mild steel and what is stainless steel and what is silver steel??
Jeff Dayman	10/12/2010 00:29:31
2356 forum posts 47 photos	You need to do some reading. Suggest getting Tubal Cain's Model Eng Handbook as a start, maybe at the show, along with your metal. Finished means the stock is to finished size and needs no further machining. Material combinations have evolved over the centuries as engineering people figured out what ran on what without burning up or seizing. Word to the wise until you get some experience - go with the combinations recommended on plans, and don't substitute, especially do not use aluminum on steam engines just because it is easy to machine. If your stock rusts when left outside it is very likely not stainless steel. Tubal Cain will tell you the rest. Do buy the book. JD
John Olsen	10/12/2010 01:08:59
1294 forum posts 108 photos 1 articles	Some brief thoughts: Silver steel is a carbon steel alloy which can be hardened. It is normally supplied ground to size, and is good for making small cutters. (Can be hardened and tempered for this purpose.) It is stronger than mild steel in the as supplied form and is accurately ground to size, so is handy if you want to make some pins, like gudgeon pins for instance. Stainless steel...comes in many variants, and is more corrosion resistant than mild steel or silver steel. Useful for piston and valve rods. Not good running against itself. Brass...again comes in quite a few variants, the sort of brass rod you will use for the engine is easy to turn for making things like glands (holding the packing or O ring that we talked about before.) It makes a reasonable bearing combination with steel or stainless steel. For an engine like yours you could use a brass piston with either an O ring or soft packing, and you will probably use brass for the main bearings. Steel. strong, easy to turn although not as easy as brass, you will mostly use it for screws and fasteners. Cast iron. used in the full size originals because it can be cast to complex shapes, and is one of the few materials that wears well against itself. Good for cylinders , pistons, and items like the bed plate of a stationary engine. Not good for highly stressed parts as it is brittle. (If you see a crankshaft that looks like a casting, it will be malleable iron or SG iron, specially treated variants that are less brittle) Bronze/gunmetal. Alloys of mainly tin and copper, mostly useful for bearings in our current context. More expensive than brass. (also used for boiler bushes where fittings screw in.) Stuart often use brass stampings for connecting rods and eccentric rods. These are OK in a model context, but in full size would normally be steel with bronze liners for the bearing surfaces. Depends how much trouble you want to go to to get an authentic look. regards John
Wolfie	10/12/2010 09:53:16
502 forum posts	Thanks for that. So what about the one designated 'finished' ??
Les Jones 1	10/12/2010 10:26:09
2292 forum posts 159 photos	Jeff Dayman has answered that question in his reply. Les.
JasonB	10/12/2010 14:32:01
25215 forum posts 3105 photos 1 articles	Can you tell us what the exact part and material is, this will narrow down what they mean by Finished, and which engine I assume its one of teh 10 range? Easy way to tell most stainless steel from Mild or silver is with a magnet, most stainless is non magnetic. There are exceptions where aluminium can be used on stem engines. For example the piston on my Fowler is HE30 alloy as this gives a smoother running engine (the originals often had hollow CI pistons to keep weight down). This is a very common use on many model traction engines.I also see no problem in using alloy for bed plates and the like. Jason PS I've just got back with a couple of big parcels from College eng but there may be a few materials left for you tomorrow. PPS Don't miss the road steam models tucked away above the entrance, its easy to pass them by. Edited By JasonB on 10/12/2010 14:34:58
Jeff Dayman	10/12/2010 15:35:33
2356 forum posts 47 photos	Jason - re your statement: " most stainless is non magnetic." This statement is not completely true. Austenitic stainlesses like the common 300 series are not magnetic but martensitic ones like 400 and 500 series are magnetic in varying degrees. For this reason magnet test alone is not totally reliable to ID stainless. I recommend Tubal Cain's book because in addition to a wealth of info on materials and machining it has a section with diagrams for spark testing materials. Along with a magnet and a file, reading this book section will allow the OP (original poster) to ID most common materials and establish their hardness, roughly. Reason I mentioned no aluminum in steam models to the OP (who is obviously just starting) is that beginners tend to go hog wild with it and make bearings, cylinders etc out of it with awful wear and corroded parts as a result. Judicious use by senior ME's like yourself with experience and judgement of required clearances can have good results as you have found. For beginners in general I stand by my "no aluminum in steam models" advice statement for minimum disappointment. Just my opinion, your mileage may vary. Before we all write out the Encyclopedia Britannica for the OP on his many questions, I suggest again he do some reading and research for himself as a starting point. After all, I'm sure that is how many of us gained experience in ME at least partly. JD
JasonB	10/12/2010 16:08:43
25215 forum posts 3105 photos 1 articles	My term "Most" refered to the 300 series which as you say are the most common and likely to be 99% of what is sold to the ME trade. And I would rather run a magnet over all my silver coloured metals than leave them all out in the rain only to find the majority covered in rust, but each to their own. I do also believe ther are certain cases where stainless steel will also rust so the rain test is not fool proof either. J Edited By JasonB on 10/12/2010 16:10:40
Terryd	10/12/2010 17:00:21
1946 forum posts 179 photos	Hi Wolfie, as already said silver steel is ground all over and looks a bit like the 'Brushed' stainless steel finish you see on some mobile phones etc. Stainless itself is usually a very good surface finish and looks quite polished. Bright mild steel (BMS or BDMS) has a good surface finish but is a sort of grey colour when compared with the others. Black mild steel (used for 'wrought iron' gates and fences etc as well as many other uses) is mild steel but still has the dark/mid bluey grey scale on from the rolling mill. The spark test mentioned is done by touching a piece of the steel you want to identify to a grinding wheel and noting the shape of the sparks made. Some people find this easy to do but I never developed the knack of. As for reading I would certainly follow John Olsen's advice. Also, ask the guys where you buy the metal to help you identify these and they will usually be pleased to help. Hi Jason, You're right, I almost missed the models next to the bar and only noticed them on my way out. I enjoyed the show but I think it was less busy than last year, at least that was my impression. Regards Terry Edited By Terryd on 10/12/2010 17:08:55
JasonB	10/12/2010 17:17:06
25215 forum posts 3105 photos 1 articles	Just to complicate the issue it is also possible to buy "precision ground mild steel" this will also have the "brushed" look that terry describes. Whatever you buy try to arrange some way of keeping the different metals apart, either by storing in separate compartments or arranging a colour coding system with a dab of paint or nail varnish on the end of the bar. J Terry I notice the newer 280s have a lever operated tailstock, something I must get round to doing on mine, you will hopefully get one with that feature.
Terryd	10/12/2010 17:19:09
1946 forum posts 179 photos	Hi Jason, I've just remembered reading Sir Alec Rose's book about sailing round the world alone in his yacht back in the 60's. He had stainless fittings on his aluminium mast and apparently had severe corrosion problems. He had them changed for mild steel (I think, my memory's not what it was) in New Zealand and had no problems afterwards, It was something to do with the electrolytic reactions involved when in a marine environment. Thinking about it it may have been Sir Francs Chichester in Gipsy Moth. I really must get my memory checked with a 50000 mile service Terry Edited By Terryd on 10/12/2010 17:27:52
,	10/12/2010 17:19:49
41 forum posts 1 photos	You said 'Stuart' at the start of your post. I always thoight that they sold KITS and not just plans so 'finished' on the parts list means that the part is supplied with the kit already finished to size and doesnt need any further machining. - or am I missing something? Phil
Stub Mandrel	10/12/2010 18:16:45
4318 forum posts 291 photos 1 articles	In Tubal Cain's 'Model Engineer's Handbook' is a diagram showing the different sparks produced by various metals when ground. I have found this the most useful book of all for reference for all sorts of things. Neil
Jeff Dayman	10/12/2010 20:59:58
2356 forum posts 47 photos	Neil, that's exactly why I recommended that book (twice) above. It's a good one all right. JD
DMB	10/12/2010 21:42:23
1585 forum posts 1 photos	Hullo Terryd, You are probably right - Stainless doesnt like seawater. I once read a corrosion article about Stainless screws and boltshaving been used on a wooden yacht and it was found that where they were hidden from sight inside the wood and permanently wet, they developed patches of corrosion which would eat the bolt away rather quickly until it failed so I understand Bronze is back in favour. John.
Chris Trice	10/12/2010 22:02:51
1376 forum posts 10 photos	You sometimes get a reaction between car alloy wheels and the steel/iron hubs they're bolted to. A friend had an old TR7 that refused to give up one of its wheels even with no wheel nuts on without an almighty whack.
Terryd	10/12/2010 22:43:35
1946 forum posts 179 photos	Posted by John Coleman 1 on 10/12/2010 21:42:23: Hullo Terryd, You are probably right - Stainless doesnt like seawater. I once read a corrosion article about Stainless screws and boltshaving been used on a wooden yacht and it was found that where they were hidden from sight inside the wood and permanently wet, they developed patches of corrosion which would eat the bolt away rather quickly until it failed so I understand Bronze is back in favour. John. Perhaps the old timers knew something after all regards Terry
Nicholas Farr	10/12/2010 22:53:37
3988 forum posts 1799 photos	Hi, the WPS no.30 Workshop Materials is another useful source of information also. Terry I think you are right the show seemed a little less busy this year, it was practically like a goast town by half past four. One or two les regular traders me thinks also. Regards Nick.
John Olsen	10/12/2010 23:00:14
1294 forum posts 108 photos 1 articles	Yes, stainless is tricky stuff and for best result you should really consult an expert. It is prone to Chloride cracking, and since seawater is full of chloride ions, the stainless steel needs to be carefully chosen for best results in marine applications. In particular, stainless will give trouble if it is buried in timber and hence not exposed to air. It is also generally a pain to machine. Another fun aspect of stainless when it is in wire form for rigging is that it will give no warning before it does go. Those of you who have ridden motorbikes will probably be familiar with the idea of inspecting the cables once in a while, and discarding if you see broken strands. Ordinary (high tensile I presume) bowden cables will give you a warning like this before failure. Stainless steel cables, as used for rigging on sailing dinghies do not give any warning before failure. I used to look at mine every time it was rigged, which is essentially every time it went sailing, and nver once found any signs of distress....but after about three seasons of use a cable would go, right next to the swaged connection of course. All this is by way of suggesting that you don't use stainless unless its properties are really needed for the job. regards john
Terryd	10/12/2010 23:21:53
1946 forum posts 179 photos	Hi John, I must admit that when I used to sail Dinghys (is that a real word, it doesn't look right) I always had galvanised steel stays and never had a problem. I just realised, that's something Nora Batty might say - 'galvanised steel stays' Terry PS I think I agree with Andrew who said in a posting that we need some more expressive Smileys, - most of those presented on the forum never get used!

1 2 3 Next > Last >>

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts

*Oct 2023: FORUM MIGRATION TIMELINE*
05/10/2023 07:57:11
Making ER11 collet chuck
05/10/2023 07:56:24
What did you do today? 2023
05/10/2023 07:25:01
Orrery
05/10/2023 06:00:41
Wera hand-tools
05/10/2023 05:47:07
New member
05/10/2023 04:40:11
Problems with external pot on at1 vfd
05/10/2023 00:06:32
Drain plug
04/10/2023 23:36:17
digi phase converter for 10 machines.....
04/10/2023 23:13:48
Winter Storage Of Locomotives
04/10/2023 21:02:11
More Latest Posts...
View All Topics

Support Our Partners

Shopping Partners

Subscription Offer

Latest "For Sale" Ads

Reeves** - Rebuilt Royal Scot by Martin Evans
by John Broughton
£300.00
BRITANNIA 5" GAUGE James Perrier
by Jon Seabright 1
£2,500.00
Drill Grinder - for restoration
by Nigel Graham 2
£0.00
WARCO WM18 MILLING MACHINE
by Alex Chudley
£1,200.00
MYFORD SUPER 7 LATHE
by Alex Chudley
£2,000.00
More "For Sale" Ads...

Latest "Wanted" Ads

D1-3 backplate
by Michael Horley
Price Not Specified
fixed steady for a Colchester bantam mark1 800
by George Jervis
Price Not Specified
lbsc pansy
by JACK SIDEBOTHAM
Price Not Specified
Pratt Burnerd multifit chuck key.
by Tim Riome
Price Not Specified
BANDSAW BLADE WELDER
by HUGH
Price Not Specified
More "Wanted" Ads...

Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues